Substrate processing method and substrate processing apparatus

Abstract

In one exemplary embodiment, the substrate processing method includes: step (a) providing a substrate having a metal-containing film and a mask disposed on the metal-containing film; step (b) forming a protective film on the mask; and step (c) etching the metal-containing film after step (b). Step (c) includes: step (c1) forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing film using a first processing gas containing a fluorine-containing gas; and step (c2) removing the second metal-containing substance using a second processing gas containing a precursor.

Description

[Technical Field]

[0001] The exemplary embodiments of the present invention relate to a substrate processing method and a substrate processing apparatus. [Previous Technology]

[0002] Patent Document 1 discloses a method for atomic layer etching (ALE). In this method, a substrate is exposed to hydrogen fluoride gas to form a fluorinated surface layer on a metal oxide film. Subsequently, the substrate is exposed to a boron-containing gas to remove the fluorinated surface layer from the metal oxide film. [Prior Art Documents] [Patent Documents]

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-26566 [Summary of the Invention]

[0004] [The problem the invention aims to solve]

[0005] This invention provides a method and apparatus for selectively etching a metal-containing substrate relative to other films. [Technical Means for Solving the Problem]

[0006] In one exemplary embodiment, a substrate processing method is provided. The method includes: step (a), which involves providing a substrate having a metal-containing film and a mask disposed on the metal-containing film; step (b), which involves forming a protective film on the mask; and step (c), which involves etching the metal-containing film after step (b); step (c) includes: step (c1), which involves forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing film using a first processing gas containing a fluorine-containing gas; and step (c2), which involves removing the second metal-containing substance using a second processing gas containing a precursor. [Effects of the Invention]

[0007] According to an exemplary embodiment, a substrate processing method and substrate processing apparatus are provided that can selectively etch a metal film relative to other films.

Implementation Method

[0009] Hereinafter, various exemplary embodiments will be described.

[0010] In one exemplary embodiment, the substrate processing method includes: step (a), which involves providing a substrate having a metal-containing film and a mask disposed on the metal-containing film; step (b), which involves forming a protective film on the mask; and step (c), which involves etching the metal-containing film after step (b); step (c) includes: step (c1), which involves forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing film using a first processing gas containing a fluorine-containing gas; and step (c2), which involves removing the second metal-containing substance using a second processing gas containing a precursor.

[0011] In the method of the above embodiment, when etching the metal-containing film, the etching of the mask is suppressed by the protective film. Therefore, the metal-containing film can be selectively etched relative to other films.

[0012] The above-described substrate processing method may further include step (d), which involves removing fluorine from the surface of the protective film using a third processing gas after step (c). In this case, more protective films can be formed subsequently in a short time.

[0013] The above-described substrate processing method may further include step (e), which is a repeat of steps (b), (c), and (d) after step (d). In this case, the etching depth of the metal-containing film can be increased.

[0014] In (b) above, the thickness of the protective film formed on the side of the mask can also decrease from the upper surface of the mask toward the metal-containing film. In this case, the thickness of the protective film formed on the metal-containing film decreases, and therefore, the etching rate of the metal-containing film increases.

[0015] In the above (d), plasma generated by the above third processing gas may also be used, and the above third processing gas may also include at least one of oxygen-containing gas, hydrogen-containing gas and nitrogen-containing gas.

[0016] The above-mentioned protective film may also contain at least one of silicon, carbon and metal.

[0017] In the above (c1), the first processing gas may also be used without generating plasma.

[0018] In the above (c1), plasma generated by the first processing gas may also be used.

[0019] The substrate may also be heated in at least one of (c1) and (c2) above. In this case, the reaction of the first metal-containing substance with the fluorine-containing gas or the reaction of the second metal-containing substance with the precursor is promoted.

[0020] The aforementioned precursor may also include a metal-containing precursor. In this case, the metal-containing precursor can react with the second metal-containing substance at low energy.

[0021] The aforementioned metal-containing precursors may also include metal complexes. In this case, another highly volatile metal complex is generated through a coordination group exchange reaction between the second metal-containing substance and the metal complex.

[0022] The above-mentioned metal complexes may also be complexes having at least one monodentate ligand selected from the group consisting of alkyl, hydride, carbonyl, halide, alkoxide, alkylamide and silylamide, or at least one chelate selected from the group consisting of β-diketone, amidoate, acetamidine, β-diketone imine, diaminoalkoxide and metallocene.

[0023] The metal contained in the above-mentioned metal-containing precursor may also be at least one selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

[0024] The aforementioned precursor may also include a precursor that does not contain metal. In this case, it is less likely that metal residue will be generated due to the reaction between the second metal-containing substance and the precursor.

[0025] The metal-free precursors mentioned above may also be at least one β-diketone selected from the group consisting of acac (acetyl acetone), hfac (hexafluoroacetyl acetone), tfac (trifluoroacetyl acetone) and tmhd (2,2,6,6-tetramethyl-3,5-heptadecyl).

[0026] The metal-containing film mentioned above may also contain at least one metal selected from the group consisting of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd and Sn.

[0027] The metal-containing film mentioned above may also be an oxide or nitride of the metal mentioned above.

[0028] The aforementioned fluorine-containing gas may also include at least one of the group consisting of hydrogen fluoride gas, fluorocarbon gas, nitrogen-containing gas and sulfur-containing gas.

[0029] In one exemplary embodiment, the substrate processing method includes: step (a) providing a substrate having an etch target film and a mask disposed on the etch target film; step (b) forming a metal-containing protective film on the mask; step (c) removing a portion of the metal-containing protective film after step (b); and step (d) etching the etch target film after step (c); wherein step (b) includes: step (b1) using a first precursor containing metal. A precursor layer is formed on the side of the aforementioned shield; and step (b2) involves using a modifying gas containing an oxidizing gas or a reducing gas to modify the aforementioned precursor layer into the aforementioned metal-containing protective film; step (c) includes: step (c1) involving using a first processing gas containing at least one of a halogen-containing gas and an oxygen-containing gas to form a second metal-containing substance from the first metal-containing substance contained in the aforementioned metal-containing protective film; and step (c2) involving using a second processing gas containing the second precursor to remove the aforementioned second metal-containing substance.

[0030] In the method of the above embodiment, a protective film containing metal can be etched with a higher selectivity relative to the etch target film and the mask.

[0031] The first precursor mentioned above may also include at least one metal selected from the group consisting of Ti, Ta, Ru, Al, Hf and Sn.

[0032] The above-mentioned halogen-containing gases may also include at least one of the groups selected from fluorine, chlorine and bromine.

[0033] The second precursor mentioned above may also include: a metal or a complex of the metals selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

[0034] The above-mentioned etched film can also be a silicon-containing film.

[0035] In one exemplary embodiment, the substrate processing apparatus includes: a chamber; a substrate support for supporting a substrate within the chamber, the substrate having a metal-containing film and a shield disposed on the metal-containing film; a gas supply unit configured to supply a first processing gas containing hydrogen fluoride gas, a second processing gas containing a precursor, a third processing gas, and a fourth processing gas for forming a protective film to the chamber; and a control unit configured to control the gas supply unit to use the fourth processing gas to form a protective film on the shield. The protective film is formed as described above; the control unit is configured to control the gas supply unit so that, after the protective film is formed, the first processing gas is used to form a second metal-containing substance from the first metal-containing substance contained in the metal-containing film; the control unit is configured to control the gas supply unit so that, after the second metal-containing substance is formed, the second processing gas is used to remove the second metal-containing substance; the control unit is configured to control the gas supply unit so that, after the second metal-containing substance is removed, the third processing gas is used to remove fluorine from the surface of the protective film.

[0036] According to the substrate processing apparatus of the above embodiment, when etching the metal-containing film, the etching of the mask is suppressed by the protective film. Therefore, the metal-containing film can be selectively etched relative to other films. Furthermore, the fluorine on the surface of the protective film is removed using a third processing gas. Therefore, more protective films can be formed thereafter in a short time.

[0037] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. Furthermore, in each drawing, the same or equivalent parts are labeled with the same symbols.

[0038] Figures 1 and 2 are schematic diagrams illustrating a substrate processing apparatus of an exemplary embodiment. The substrate processing apparatus of this embodiment is, for example, a plasma processing system.

[0039] In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to the gas supply unit 20 (described later), and the gas outlet is connected to the exhaust system 40 (described later). The substrate support unit 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0040] The plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied to the plasma processing space. The plasma formed in the plasma processing space can also be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR), helicon wave plasma (HWP), or surface wave plasma (SWP), etc. Furthermore, various types of plasma generation units, including AC (Alternating Current) plasma generation units and DC (Direct Current) plasma generation units, can also be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes RF (Radio Frequency) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 200 kHz to 150 MHz.

[0041] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various steps described herein. The control unit 2 may be configured to control various elements of the plasma processing apparatus 1 to perform the various steps described herein. In one embodiment, part or all of the control unit 2 may also be included in the plasma processing apparatus 1. The control unit 2 may, for example, include a computer 2a. The computer 2a may, for example, include a processing unit (CPU: Central Processing Unit) 2a1, a memory unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control actions based on a program stored in the memory unit 2a2. The memory unit 2a2 may also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 can also communicate with the plasma processing device 1 via communication lines such as LAN (Local Area Network).

[0042] Hereinafter, an example of the configuration of the plasma processing system will be described. The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a control unit 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a cluster nozzle 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The cluster nozzle 13 is disposed above the substrate support unit 11. In one embodiment, the cluster nozzle 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the cluster nozzle 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s, and at least one gas outlet for discharging gas from the plasma processing space. The sidewall 10a is grounded. The cluster head 13 and the substrate support portion 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0043] The substrate support portion 11 includes a body portion 111 and an annular component 112. The body portion 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W, and an annular region (annular support surface) 111b for supporting the annular component 112. The annular region 111b of the body portion 111 surrounds the central region 111a of the body portion 111 when viewed from above. The substrate W is disposed on the central region 111a of the body portion 111, and the annular component 112 is disposed on the annular region 111b of the body portion 111 in such a way that it surrounds the substrate W on the central region 111a of the body portion 111. In one embodiment, the body portion 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The annular component 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Furthermore, although not shown in the figures, the substrate support portion 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck, the annular component 112, and the substrate to a target temperature. The temperature control module may also include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path. Additionally, the substrate support portion 11 may also include a heat transfer gas supply portion configured to supply heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0044] The cluster injector 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The cluster injector 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlets 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the plurality of gas inlets 13c. Furthermore, the cluster injector 13 includes a conductive member. The conductive member of the cluster injector 13 functions as an upper electrode. In addition to the cluster injector 13, the gas inlet may also include one or more side gas injectors (SGIs) mounted on one or more openings formed on the sidewall 10a.

[0045] The gas supply unit 20 may also include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from its respective corresponding gas source 21 to the cluster nozzle 13 via its respective corresponding flow controller 22. Each flow controller 22 may, for example, include a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include one or more flow modulation devices for modulating or pulsed the flow rate of the at least one process gas.

[0046] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive members of the substrate support portion 11 and / or the conductive members of the cluster head 13. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Furthermore, by supplying a bias RF signal to the conductive members of the substrate support portion 11, a bias potential is generated in the substrate W, thereby enabling the feeding of ionic components from the formed plasma into the substrate W.

[0047] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is configured to couple with a conductive member of the substrate support 11 and / or a conductive member of the cluster head 13 via at least one impedance matching circuit to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may also be configured to generate a plurality of source RF signals with different frequencies. One or more source RF signals generated are supplied to the conductive member of the substrate support 11 and / or the conductive member of the cluster head 13. The second RF generating unit 31b is configured to couple with a conductive member of the substrate support 11 via at least one impedance matching circuit to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In another embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals with different frequencies. One or more of the generated bias RF signals are supplied to the conductive members of the substrate support unit 11. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may also be pulsed.

[0048] Furthermore, the power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generating unit 32a and a second DC generating unit 32b. In one embodiment, the first DC generating unit 32a is configured as a conductive member connected to the substrate support 11 to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the first DC signal may also be applied to other electrodes, such as electrodes within the electrostatic chuck. In one embodiment, the second DC generating unit 32b is configured as a conductive member connected to the cluster head 13 to generate a second DC signal. The generated second DC signal is applied to the conductive member of the cluster head 13. In various embodiments, at least one of the first and second DC signals may also be pulsed. Furthermore, the first and second DC generating units 32a and 32b and the RF power supply 31 can be provided simultaneously, or the first DC generating unit 32a can be provided to replace the second RF generating unit 31b.

[0049] The exhaust system 40 may be connected, for example, to a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may also include a turbomolecular pump, a dry vacuum pump, or a combination thereof.

[0050] FIG3 is a partially enlarged cross-sectional view of an example substrate. As shown in FIG3, in one embodiment, the substrate W includes a metal-containing film MF and a mask MK. The mask MK is disposed on the metal-containing film MF. The substrate W may also include a substrate region UR. The substrate region UR may contain silicon. The metal-containing film MF may be disposed on the substrate region UR.

[0051] The metal-containing film MF may also contain at least one of oxygen and nitrogen. The metal-containing film MF may also contain at least one of metal oxide and metal nitride. The metal-containing film MF may also contain at least one of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd and Sn.

[0052] The mask MK may also contain silicon. The mask MK may also contain at least one of silicon oxide and silicon nitride. The mask MK may also contain carbon (organic material). The mask MK may also contain at least one of photoresist, spin-coated carbon, amorphous carbon and tungsten carbide. The mask MK may also have at least one recess RS. Each recess RS may also be an opening.

[0053] Figure 4 is a flowchart of an exemplary embodiment of a substrate processing method. The substrate processing method shown in Figure 4 (hereinafter referred to as "method MT1") can be executed by the substrate processing apparatus of the above embodiment. Method MT1 may include steps ST1 to ST5. Steps ST1 to ST5 may be executed sequentially. Step ST5 may also be omitted.

[0054] Hereinafter, method MT1 will be described with reference to Figures 4 to 8. When using the plasma processing apparatus 1, method MT1 can be executed in the plasma processing apparatus 1 by controlling each part of the plasma processing apparatus 1 through the control unit 2. In method MT1, the metal-containing film MF can be etched. Steps ST1 to ST5 can also be performed in-situ. That is, method MT1 can be executed without removing the substrate W from the plasma processing chamber 10.

[0055] (Step ST1) In step ST1, the substrate W shown in FIG3 is provided. As shown in FIG2, the substrate W can be supported in the plasma processing chamber 10 by the substrate support 11.

[0056] (Step ST2) Figure 5 is a partially enlarged cross-sectional view of a substrate in one example of the step of forming a protective film on a mask. In step ST2, a protective film PR is formed on the mask MK. The protective film PR can be formed by atomic layer deposition (ALD), molecular layer deposition (MLD), or chemical vapor deposition (CVD). A fourth processing gas can be used to form the protective film PR. The fourth processing gas is supplied from the gas supply unit 20 into the plasma processing chamber 10. In the plasma processing chamber 10, the substrate W is exposed to the fourth processing gas. When the protective film PR is formed by ALD or MLD, a precursor gas and a modified gas are used as the fourth processing gas.

[0057] The protective film PR can be formed on the upper surface MKt and side surfaces MKs of the mask MK. The thickness of the protective film PR formed on the upper surface MKt of the mask MK is greater than the thickness of the protective film PR formed on the side surfaces MKs of the mask MK. The thickness of the protective film PR formed on the side surfaces MKs of the mask MK can also decrease from the upper surface MKt of the mask MK toward the metal-containing film MF. That is, the protective film PR can also be a subconformal film. At the bottom of the recess RS of the mask MK, the protective film PR may not be formed on the metal-containing film MF. The thickness of the protective film PR formed at the bottom of the recess RS of the mask MK is less than the thickness of the protective film PR formed on the upper surface MKt and side surfaces MKs of the mask MK.

[0058] The protective film PR can also be a conformal film. In this case, for example, the protective film PR formed at the bottom of the recess RS of the mask MK can be selectively removed by anisotropic etching. In this way, the protective film PR at the bottom of the recess RS of the mask MK can be removed while leaving the protective film PR on the upper surface MKt and the side surface MKs of the mask MK.

[0059] The protective film PR may also contain at least one of silicon, carbon and metal.

[0060] When the protective film PR has a silicon oxide film formed by ALD or MLD, silicon-containing gases such as aminosilane, SiCl4 or SiF4 can be used as precursor gases, and oxygen-containing gases such as oxygen can be used as modifier gases.

[0061] When the protective film PR has a silicon nitride film formed by ALD or MLD, silicon-containing gases such as aminosilane, SiCl4, dichlorosilane, and hexachlorosilane can be used as precursor gases. Nitrogen-containing gases such as ammonia and nitrogen can be used as modifier gases.

[0062] When the protective film PR has an organic film formed by ALD, epoxides, carboxylic acids, carboxylic halides, carboxylic anhydrides, isocyanates, or phenols can be used as precursor gases. Inorganic compound gases with NH bonds, inert gases, mixtures of N2 and H2, H2O gas, or mixtures of H2 and O2 can be used as modifier gases.

[0063] When the protective film PR has an organic film formed by MLD, isocyanate, carboxylic acid, or carboxylic acid halide can be used as the precursor gas, and amine or compound having a hydroxyl group can be used as the modifier gas. Alternatively, carboxylic anhydride can be used as the precursor gas, and amine can be used as the modifier gas. Alternatively, bisphenol A can be used as the precursor gas, and diphenyl carbonate or epichlorohydrin can be used as the modifier gas.

[0064] When the protective film PR has a metal-containing film formed by ALD or MLD, a gas containing metals such as Ti, Ta, Ru, Al, Hf or Sn, or a gas containing oxides, nitrides, sulfides or halides of such metals, can be used as a precursor gas. Oxidizing or reducing gases such as hydrogen-containing gases (H2, etc.), oxygen-containing gases (O2, etc.), mixed gases of H2 and N2, and gases containing hydrogen and nitrogen (NH3, etc.) can be used as the modifying gas.

[0065] Alternatively, step ST12, which removes the protective film PR formed on the bottom of the recess RS of the mask MK, can be performed after step ST2. Step ST12 can also be performed before step ST3. For example, if the protective film PR is a silicon-containing film, in step ST12, the protective film PR formed on the bottom of the recess RS can be removed by plasma generated by a fluorine-containing gas. For example, if the protective film PR is an organic film, in step ST12, the protective film PR formed on the bottom of the recess RS can be removed by O2 gas or H2 gas.

[0066] (Step ST3) In step ST3, the metal-containing film MF is etched. The metal-containing film MF can be etched by atomic layer etching (ALE). Step ST3 includes steps ST31 and ST32. Step ST32 is performed after step ST31. Steps ST31 and ST32 can also be repeated alternately in step ST3.

[0067] (Step ST31) FIG6 is a partially enlarged cross-sectional view of a substrate in an example of the step of forming the second metal-containing material. In step ST31, a first processing gas G1 containing fluorine gas is used to form a second metal-containing material MS2 from the first metal-containing material MS1 (refer to FIG5) contained in the metal-containing film MF. The first metal-containing material MS1 may be located on the surface of the metal-containing film MF. The first processing gas G1 etches the protective film PR, thereby thinning the protective film PR on the mask MK and removing the protective film PR on the metal-containing film MF. Thereby, the surface of the metal-containing film MF is exposed to the first processing gas G1. As a result, the first metal-containing material MS1 reacts with the first processing gas G1. The first processing gas G1 is supplied from the gas supply unit 20 into the plasma processing chamber 10. In the plasma processing chamber 10, the substrate W is exposed to the first processing gas G1.

[0068] Fluorine-containing gases may also include at least one of hydrogen fluoride (HF), fluorocarbon, nitrogen-containing, and sulfur-containing gases. Fluorocarbon gases may include at least one of C4F6, C4F8, C3F8, and CF4. Nitrogen-containing gases may include NF3. Sulfur-containing gases may include SF6.

[0069] The example of the first metal-containing substance MS1 is the same as the example of the constituent material of the metal-containing film MF. The second metal-containing substance MS2 can be produced by reacting the first metal-containing substance MS1 with a fluorine-containing gas. The second metal-containing substance MS2 may contain a metal that is the same as the metal contained in the first metal-containing substance MS1, and fluorine. The second metal-containing substance MS2 is, for example, a metal fluoride. In one example, the first metal-containing substance MS1 contains aluminum oxide, and the fluorine-containing gas contains hydrogen fluoride gas. In this case, the second metal-containing substance MS2 contains aluminum fluoride.

[0070] In step ST31, the surface PRs of the protective film PR can be fluorinated by reacting the surface PRs of the protective film PR with a fluorine-containing gas. As a result, fluorine can remain on the surface PRs of the protective film PR.

[0071] In step ST31, the first processing gas G1 may be used without generating plasma, or plasma generated by the first processing gas G1 may be used. In the case where no plasma is generated, the first processing gas G1 may also contain hydrogen fluoride gas.

[0072] In step ST31, the substrate W may also be heated. The temperature of the substrate support portion 11 may be 100°C or higher, 150°C or higher, or 200°C or higher. The temperature of the substrate support portion 11 may be 450°C or lower. Heating may be performed by plasma generated in the plasma processing chamber 10 or by a temperature control module in the substrate support portion 11. Heating promotes the reaction between the first metal-containing substance MS1 and the fluorine-containing gas.

[0073] A rinsing step may also be performed after step ST31. In the rinsing step, after the rinsing gas is supplied into the plasma processing chamber 10, the rinsing gas is discharged. The rinsing gas is, for example, an inert gas such as nitrogen or argon.

[0074] (Step ST32) FIG7 is a partially enlarged cross-sectional view of a substrate in one example of the step of removing the second metal-containing substance. In step ST32, the second metal-containing substance MS2 is removed using a second processing gas G2 containing a precursor. The second processing gas G2 is supplied from the gas supply unit 20 into the plasma processing chamber 10. In step ST32, the second processing gas G2 can be used without generating plasma. Inside the plasma processing chamber 10, the substrate W is exposed to the second processing gas G2.

[0075] The precursor may also include a metal-containing precursor. The metal-containing precursor may also include a metal complex. The metal complex may be a complex with a monodentate ligand or a chelate. The monodentate ligand may be at least one of alkyl, hydride, carbonyl, halide, alkoxide, alkylamide, and silylamide. The chelate may be at least one of β-diketone, amidoside, acetamidine, β-diketone imine, diaminoalkoxide, and metallocene. The β-diketone may be at least one of acac (acetylacetone), hfac (hexafluoroacetylacetone), tfac (trifluoroacetylacetone), and tmhd (2,2,6,6-tetramethyl-3,5-heptadecane).

[0076] The metal contained in the metal precursor may be at least one of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

[0077] The precursor may also include a metal-free precursor. The metal-free precursor may also include a carbon-containing precursor. The carbon-containing precursor may be at least one of an alcohol, β-diketone, amidine, acetamine, and β-diketone imine. The β-diketone may be at least one of acac (acetylacetone), hfac (hexafluoroacetylacetone), tfac (trifluoroacetylacetone), and tmhd (2,2,6,6-tetramethyl-3,5-heptadecyl dione).

[0078] In step ST32, a volatile third metal-containing substance MS3 can be generated by the reaction of the second metal-containing substance MS2 with the precursor. This removes the second metal-containing substance MS2. When the precursor contains a metal-containing precursor, the metal-containing precursor can react with the second metal-containing substance at low energy. When the metal-containing precursor contains a metal complex, a highly volatile metal complex is generated by the coordination group exchange reaction between the second metal-containing substance MS2 and the metal complex. In one example, the second metal-containing substance MS2 contains aluminum fluoride, and the metal-containing precursor contains tin(II) acetone (Sn(acac)2). When the precursor does not contain a metal precursor, metal residue is less likely to be generated by the reaction of the second metal-containing substance with the precursor. When the non-metal-containing precursor contains a carbon-containing precursor, residue containing carbon compounds is generated. Residues containing carbon compounds can be removed relatively easily.

[0079] In step ST32, the substrate W can also be heated in the same manner as in step ST31. Heating promotes the reaction between the second metal-containing substance MS2 and the precursor.

[0080] Alternatively, after step ST32, a rinsing step may be performed in the same manner as the rinsing step performed after step ST31.

[0081] (Step ST4) FIG8 is a partially enlarged cross-sectional view of a substrate in one example of the step of modifying the surface of the protective film. In step ST4, the surface PRs of the protective film PR are modified. In step ST4, the fluorine on the surface PRs of the protective film PR is removed using a third processing gas. In this embodiment, plasma PL generated by the third processing gas is used in step ST4. The plasma PL can be generated by the third processing gas supplied from the gas supply unit 20 to the plasma processing chamber 10 via the plasma generation unit 12. In the plasma processing chamber 10, the substrate W is exposed to the plasma PL. Alternatively, the third processing gas can be used without generating plasma.

[0082] When the protective film PR contains silicon, after step ST31, Si-F bonds may remain on the surface PRs of the protective film PR. In this case, if plasma PL generated by a third processing gas containing oxygen gas is used, the fluorine atoms on the surface PRs of the protective film PR are replaced by OH groups. As a result, Si-OH bonds are formed on the surface PRs of the protective film PR. If plasma PL generated by a third processing gas containing hydrogen gas is used, the fluorine atoms on the surface PRs of the protective film PR are replaced by hydrogen atoms. As a result, Si-H bonds are formed on the surface PRs of the protective film PR. If plasma PL generated by a third processing gas containing nitrogen gas is used, the fluorine atoms on the surface PRs of the protective film PR are replaced by nitrogen atoms. As a result, Si-N bonds are formed on the surface PRs of the protective film PR.

[0083] When the protective film PR contains carbon, after step ST31, CF bonds may exist on the surface PRs of the protective film PR. In this case, if plasma PL generated by a third processing gas containing oxygen or hydrogen is used, the fluorine atoms on the surface PRs of the protective film PR are replaced by H groups. As a result, CH bonds are formed on the surface PRs of the protective film PR. This is due to the volatilization of the generated carbon monoxide. If plasma PL generated by a third processing gas containing nitrogen is used, the fluorine atoms on the surface PRs of the protective film PR are replaced by nitrogen atoms. As a result, CN bonds are formed on the surface PRs of the protective film PR. Alternatively, if plasma PL generated by a third processing gas containing nitrogen is used, the surface PRs of the protective film PR are cut. As a result, the constituent material of the protective film PR is exposed on the surface PRs of the protective film PR. When the constituent material contains CH bonds, the CH bonds are exposed on the surface PRs of the protective film PR.

[0084] (Step ST5) In step ST5, steps ST2, ST3, and ST4 are repeated. Steps ST2, ST3, and ST4 may also be repeated multiple times. By means of step ST5, the etching depth of the metal film MF can be increased.

[0085] According to the above method MT1, when etching the metal-containing film MF, the etching of the mask MK is suppressed by the protective film PR. Therefore, the metal-containing film MF can be selectively etched relative to other films. Furthermore, the fluorine on the surface PRs of the protective film PR is removed by step ST4. When fluorine remains on the surface PRs of the protective film PR, the time until the deposition of the protective film PR begins tends to be longer. In the above method MT1, the fluorine on the surface PRs of the protective film PR is removed in step ST4, therefore, more protective film PR can be formed in a shorter time thereafter.

[0086] In step ST2, the thickness of the protective film PR formed on the side surface MKs of the mask MK decreases from the upper surface MKt of the mask MK toward the metal-containing film MF. In the above case, the thickness of the protective film PR formed on the metal-containing film MF decreases. Therefore, the protective film PR on the metal-containing film MF can be removed in a short time, thus increasing the etching rate of the metal-containing film MF.

[0087] Various exemplary embodiments have been described above, but the present invention is not limited to the above exemplary embodiments, and various additions, omissions, substitutions, and modifications can be made. Furthermore, elements from different embodiments can be combined to form other embodiments. Hereinafter, examples of other embodiments will be described, but processing methods that are the same as those in the above exemplary embodiments will be omitted or simplified in the description.

[0088] (Other Embodiment 1) The substrate processing apparatus may also omit the plasma generation unit 12. In this case, plasma processing is not performed within the chamber of the substrate processing apparatus. Method MT1 can also be performed using this type of substrate processing apparatus.

[0089] (Other Embodiment 2) The first processing gas G1 may also contain a halogen-containing gas. For example, the first processing gas G1 may contain at least one of a chlorine-containing gas and a bromine-containing gas instead of the aforementioned fluorine-containing gas, or may contain at least one of a chlorine-containing gas and a bromine-containing gas while containing a fluorine-containing gas. The chlorine-containing gas may also contain at least one of chlorine gas (Cl2) and hydrogen chloride gas (HCl). The bromine-containing gas may also contain at least one of bromine gas (Br2) and hydrogen bromide gas (HBr). In step ST31, when plasma is generated from the first processing gas G1, the halogen-containing gas may also contain at least one of silicon and carbon.

[0090] When the first processing gas G1 contains a halogen-containing gas, the second metal-containing substance M2 generated in step ST31 can be formed by the reaction of the first metal-containing substance MS1 with the halogen-containing gas. The second metal-containing substance MS2 may contain the same metal as the metal contained in the first metal-containing substance MS1, and a halogen. The second metal-containing substance MS2 is, for example, a metal halide. Specifically, the second metal-containing substance MS2 may be a metal fluoride, a metal chloride, or a metal bromide. Even when the second metal-containing substance MS2 is a metal halide (metal chloride or metal bromide) other than a metal fluoride, the second metal-containing substance MS2 can be removed by the second processing gas G2 containing the precursor.

[0091] (Other embodiments 3) The first processing gas G1 may also contain an oxygen-containing gas instead of a halogen-containing gas, or contain an oxygen-containing gas while containing a halogen-containing gas. For example, the first processing gas G1 may contain at least one of oxygen (O2), carbon monoxide (CO) gas and carbon dioxide (CO2) gas as an oxygen-containing gas.

[0092] When the first processing gas G1 contains oxygen-containing gas, the second metal-containing substance M2 generated in step ST31 can be formed by the reaction of the first metal-containing substance MS1 with the oxygen-containing gas. The second metal-containing substance MS2 may contain a metal identical to the metal contained in the first metal-containing substance MS1, and oxygen. The second metal-containing substance MS2 is, for example, a metal oxide. When the second metal-containing substance MS2 is a metal oxide, the second metal-containing substance MS2 can be removed by the aforementioned second processing gas G2 containing a metal-free precursor.

[0093] (Other Embodiment 4) FIG9 is a flowchart of the substrate processing method of Other Embodiment 4. The substrate processing method shown in FIG9 (hereinafter referred to as "Method MT2") includes steps ST1 to ST5 in the same manner as Method MT1. Method MT2 includes step ST33 after step ST32 and before step ST4. Step ST33 is the step of exposing the substrate W to plasma generated by the fifth processing gas described below, wherein the fifth processing gas includes at least one of a fluorine-containing gas, an oxygen-containing gas, a hydrogen-containing gas, and a nitrogen-containing gas. The fluorine-containing gas may also include at least one of a fluorocarbon gas, a nitrogen-containing gas, and a sulfur-containing gas. The fluorocarbon gas may include at least one of a C4F6 gas, a C4F8 gas, a C3F8 gas, and a CF4 gas. The nitrogen-containing gas may include NF3 gas. The sulfur-containing gas may include SF6 gas. The oxygen-containing gas may also include at least one of an oxygen gas, a carbon monoxide gas, and a carbon dioxide gas. The hydrogen-containing gas may also include hydrogen. The nitrogen-containing gas may also include nitrogen. When the precursor used in step ST32 contains Sn, the fifth processing gas may also contain at least one of hydrogen, CH4, and carbon monoxide. When the precursor used in step ST32 contains Si, Ge, or B, the fifth processing gas may also contain a fluorine-containing gas. When the precursor used in step ST32 contains Pb, Ni, Al, Zn, Hf, or Zr, the fifth processing gas may also contain at least one of CH4 and carbon monoxide. When the precursor used in step ST32 contains a non-metallic precursor, the fifth processing gas may also contain at least one of hydrogen and oxygen.

[0094] According to the above method MT2, the following residues (e.g., residues from the precursor) can be removed, which are present on the substrate W after the second metal-containing substance MS2 is removed.

[0095] (Other Embodiment 5) This embodiment can be applied to the etching of films containing metal, and not only to the etching of metal-containing films MF. FIG10 is a flowchart of the substrate processing method of Other Embodiment 5. The substrate processing method shown in FIG10 (hereinafter referred to as "Method MT3") may include steps ST1a to ST5a. Steps ST1a to ST5a may be performed sequentially. Method MT3 may also exclude step ST4a.

[0096] (Step ST1a) In step ST1a, a substrate Wa as shown in FIG11 is provided. The substrate Wa has an etch target film EF and a mask MKa. The substrate Wa may also have a substrate region UR under the etch target film EF. The etch target film EF may be a silicon-containing film. The etch target film EF may be at least one of silicon oxide film, silicon nitride film and polysilicon film, or may be a laminated film containing two or more of these.

[0097] The mask MK may also have at least one recess RS. The mask MKa may also contain silicon. The mask MKa may also contain at least one of silicon oxide and silicon nitride. The mask MKa may also contain carbon (organic material). The mask MKa may also contain at least one of photoresist, spin-coated carbon, amorphous carbon and tungsten carbide. The mask MKa may also contain metal. The mask MKa may also contain at least one of tin (Sn), tellurium (Te), antimony (Sb), indium (In), silver (Ag), titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), germanium (Ge) and hafnium (Hf). The mask MKa may contain oxides of Sn or hydroxides of Sn.

[0098] (Step ST2a) In step ST2a, a metal-containing protective film PRa as shown in FIG. 12 is formed on the mask MKa. The metal-containing protective film PRa can be formed by atomic layer deposition (ALD), molecular layer deposition (MLD), or chemical vapor deposition (CVD). The metal-containing protective film PRa can be a conformal film or a sub-conformal film. At the bottom of the recess RSa of the mask MKa, the metal-containing protective film PRa may not be formed on the etched target film EF.

[0099] When the protective film PRa containing metal is formed by ALD or MLD, step ST2a may also include steps ST21a and ST22a. Step ST22a is performed after step ST21a. In step ST2a, steps ST21a and ST22a may also be repeated alternately.

[0100] (Step ST21a) In step ST21a, a precursor layer is formed on the shield MKA using a gas containing a first precursor of metal. The precursor layer may also be formed on the side of the shield MKA. The precursor layer may or may not be formed on the upper surface of the shield MKA. The precursor layer may or may not be formed at the bottom of the recess RSa of the shield MKA. The gas containing the first precursor may be a gas containing metals such as Ti, Ta, Ru, Al, Hf, or Sn, or a gas containing metals such as oxides, nitrides, sulfides, or halides of such metals.

[0101] (Step ST22a) In step ST22a, a modifier gas containing an oxidizing gas or a reducing gas is used to modify the precursor layer to form a protective film PRa containing metal. As the modifier gas, oxidizing gases or reducing gases such as hydrogen-containing gases (H2, etc.), oxygen-containing gases (O2, etc.), mixed gases of H2 and N2, and gases containing hydrogen and nitrogen (NH3, etc.) can be used.

[0102] (Step ST3a) In step ST3a, a portion of the metal-containing protective film PRa is etched. The remaining portion of the metal-containing protective film PRa is not etched. The portion of the metal-containing protective film PRa can be etched by atomic layer etching (ALE). Step ST3a includes steps ST31a and ST32a. Step ST32a is performed after step ST31a. Steps ST31a and ST32a can also be repeated alternately in step ST3a.

[0103] (Step ST31a) In step ST31a, as shown in FIG13, a first processing gas G1a containing at least one of a halogen-containing gas and an oxygen-containing gas is used to form a second metal-containing substance MS2 from a first metal-containing substance MS1 contained in a metal-containing protective film PRa. The first processing gas G1a can be the same gas as the first processing gas G1. The first metal-containing substance MS1 filling the recesses created by the surface roughness of the shield MKa may also not react with the first processing gas G1a.

[0104] (Step ST32a) In step ST32a, as shown in FIG14, the second metal-containing substance MS2 is removed using the second processing gas G2a containing the precursor. The same precursor contained in the second processing gas G2 can be used as the second precursor.

[0105] (Step ST4a) In step ST4a, steps ST2a and ST3a are repeated. Each of steps ST2a and ST3a may also be repeated multiple times. The etching amount of the protective film PRa containing metal can be controlled according to the number of repetitions of steps ST2a and ST3a.

[0106] (Step ST5a) In step ST5a, the target film EF is etched through a recess RS (opening) in a mask MKa containing a metal protective film PRa. The target film EF can also be etched by plasma generated by the sixth processing gas. For example, when the target film EF is a silicon-containing film, the sixth processing gas may also contain a fluorine-containing gas. The fluorine-containing gas may also contain at least one of hydrogen fluoride gas (HF gas), fluorocarbon gas, and hydrofluorocarbon gas.

[0107] According to method MT3, in step ST3a, the protective film PRa containing metal can be etched with a higher selectivity relative to the etch target film EF and the mask MKa. Furthermore, according to method MT3, when the surface roughness of the mask MKa is large, the surface roughness of the mask MKa can be improved.

[0108] As should be understood from the above description, the various embodiments of the present invention are described in this specification for illustrative purposes, and various modifications can be made without departing from the scope and spirit of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are shown by way of the appended claims.

[0109] Various exemplary embodiments included in the present invention are described below in (Appendix 1) to (Appendix 24).

[0110] (Appendix 1) A substrate processing method comprising: step (a) providing a substrate having a metal-containing film and a mask disposed on the metal-containing film; step (b) forming a protective film on the mask; and step (c) etching the metal-containing film after step (b); step (c) comprising: step (c1) forming a second metal-containing substance from a first metal-containing substance contained in the metal-containing film using a first processing gas containing a fluorine-containing gas; and step (c2) removing the second metal-containing substance using a second processing gas containing a precursor.

[0111] (Note 2) The method described in Note 1 further includes the following step (d), which is to remove the fluorine from the surface of the protective film using a third processing gas after (c) above.

[0112] (Note 3) The method described in Note 2 further includes the following step (e), which is a repeat of (b), (c) and (d) above, following (d) above.

[0113] (Note 4) The method described in any of Notes 1 to 3, wherein in (b) above, the thickness of the protective film formed on the side of the shield decreases from the upper surface of the shield toward the metal-containing film.

[0114] (Note 5) The method described in Note 2, wherein plasma generated by the third processing gas is used in (d) above, the third processing gas comprising at least one of oxygen-containing gas, hydrogen-containing gas and nitrogen-containing gas.

[0115] (Note 6) The method described in any of Notes 1 to 5, wherein the protective film contains at least one of silicon, carbon and metal.

[0116] (Note 7) The method described in any of Notes 1 to 6, wherein in (c1) above, no plasma is generated and the first processing gas described above is used.

[0117] (Note 8) The method described in any of Notes 1 to 6, wherein plasma generated from the first processing gas described above is used in (c1) above.

[0118] (Note 9) The method described in any one of Notes 1 to 8, wherein the substrate is heated in at least one of (c1) and (c2) above.

[0119] (Note 10) The method described in any of Notes 1 to 9, wherein the precursor includes a precursor containing a metal.

[0120] (Note 11) The method described in Note 10, wherein the aforementioned metal-containing precursor comprises a metal complex.

[0121] (Note 12) The method described in Note 11, wherein the metal complex is a complex having at least one monodentate ligand selected from the group consisting of alkyl, hydride, carbonyl, halide, alkoxide, alkylamide and silylamide, or at least one chelate selected from the group consisting of β-diketone, amidoate, acetamidine, β-diketone imine, diaminoalkoxide and metallocene.

[0122] (Note 13) The method described in any of Notes 10 to 12, wherein the metal contained in the aforementioned metal-containing precursor is selected from at least one of the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

[0123] (Note 14) The method described in any of Notes 1 to 13, wherein the aforementioned precursor includes a precursor that does not contain metal.

[0124] (Note 15) The method described in Note 14, wherein the metal-free precursor is selected from at least one β-diketone from the group consisting of acac (acetyl acetone), hfac (hexafluoroacetyl acetone), tfac (trifluoroacetyl acetone) and tmhd (2,2,6,6-tetramethyl-3,5-heptadecyl dione).

[0125] (Note 16) The method described in any of Notes 1 to 15, wherein the metal-containing film comprises at least one metal selected from the group consisting of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd and Sn.

[0126] (Note 17) The method described in Note 16, wherein the metal-containing film is an oxide or nitride of the metal.

[0127] (Note 18) The method described in any of Notes 1 to 17, wherein the fluorine-containing gas comprises at least one selected from the group consisting of hydrogen fluoride gas, fluorocarbon gas, nitrogen-containing gas and sulfur-containing gas.

[0128] (Appendix 19) A substrate processing method, comprising: step (a) providing a substrate having an etch target film and a mask disposed on the etch target film; step (b) forming a metal-containing protective film on the mask; step (c) removing a portion of the metal-containing protective film after step (b); and step (d) etching the etch target film after step (c); wherein step (b) comprises: step (b1) forming a precursor layer on a side of the mask using a first precursor containing metal; and step (b2) modifying the precursor layer into the metal-containing protective film using a modifying gas containing an oxidizing gas or a reducing gas; wherein step (c) comprises: Step (c1) involves using a first processing gas containing at least one of a halogen-containing gas and an oxygen-containing gas to form a second metal-containing substance from the first metal-containing substance contained in the aforementioned metal-containing protective film; and step (c2) involves using a second processing gas containing a second precursor to remove the aforementioned second metal-containing substance.

[0129] (Note 20) The method described in Note 19, wherein the first precursor comprises at least one metal selected from the group consisting of Ti, Ta, Ru, Al, Hf and Sn.

[0130] (Note 21) The method described in Note 19 or 20, wherein the halogen-containing gas comprises at least one selected from the group consisting of fluorine, chlorine and bromine.

[0131] (Note 22) The method described in any of Notes 19 to 21, wherein the second precursor comprises: a metal or a complex of the metals comprising at least one selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

[0132] (Note 23) The method described in any of Notes 19 to 22, wherein the etched object film is a silicon film.

[0133] (Appendix 24) A substrate processing apparatus comprising: a chamber; a substrate support for supporting a substrate in the chamber, the substrate having a metal-containing film and a shield disposed on the metal-containing film; a gas supply unit configured to supply a first processing gas containing hydrogen fluoride gas, a second processing gas containing a precursor, a third processing gas, and a fourth processing gas for forming a protective film to the chamber; and a control unit; the control unit configured to control the gas supply unit to form the protective film on the shield using the fourth processing gas; the control unit configured to control the gas supply unit to form a second metal-containing substance from a first metal-containing substance contained in the metal-containing film using the first processing gas after the protective film is formed; and the control unit configured to control the gas supply unit to remove the second metal-containing substance using the second processing gas after the second metal-containing substance is formed. The control unit is configured to control the gas supply unit so that, after the second metal-containing substance is removed, the third processing gas is used to remove the fluorine from the surface of the protective film. [Simplified Explanation of the Diagram]

[0008] Figure 1 is a schematic diagram showing a substrate processing apparatus according to an exemplary embodiment. Figure 2 is a schematic diagram showing a substrate processing apparatus according to an exemplary embodiment. Figure 3 is a partially enlarged cross-sectional view of an example substrate. Figure 4 is a flowchart of a substrate processing method according to an exemplary embodiment. Figure 5 is a partially enlarged cross-sectional view of an example substrate in the step of forming a protective film on a mask. Figure 6 is a partially enlarged cross-sectional view of an example substrate in the step of forming a second metal-containing substance. Figure 7 is a partially enlarged cross-sectional view of an example substrate in the step of removing the second metal-containing substance. Figure 8 is a partially enlarged cross-sectional view of an example substrate in the step of surface modification of the protective film. Figure 9 is a flowchart of a substrate processing method according to an exemplary embodiment. Figure 10 is a flowchart of a substrate processing method according to an exemplary embodiment. Figure 11 is a partially enlarged cross-sectional view of an example substrate. Figure 12 is a partially enlarged cross-sectional view of an example substrate in the step of forming a metal-containing protective film on a mask. Figure 13 is a partially enlarged cross-sectional view of a substrate in one example of the step of forming the second metal-containing material. Figure 14 is a partially enlarged cross-sectional view of a substrate in one example of the step of removing the second metal-containing material.

Claims

1. A substrate processing method, comprising: Step (a) involves providing a substrate having a metal film and a mask disposed on the metal film. Step (b) involves forming a protective film on the aforementioned mask; and step (c) involves etching the aforementioned metal-containing film after step (b); in step (b), the thickness of the protective film formed on the side of the aforementioned mask decreases from the upper surface of the aforementioned mask toward the aforementioned metal-containing film; step (c) includes: step (c1) using a first processing gas containing a fluorine-containing gas to form a second metal-containing substance from the first metal-containing substance contained in the aforementioned metal-containing film; and step (c2) using a second processing gas containing a precursor to remove the aforementioned second metal-containing substance.

2. The method of claim 1 further includes step (d), which is performed after step (c) above, using a third processing gas to remove fluoride from the surface of the protective film.

3. The method of claim 2 further includes step (e), which is a repeat of (b), (c) and (d) above, following (d) above.

4. The method of claim 2, wherein plasma generated by the third processing gas is used in step (d) above, the third processing gas comprising at least one of an oxygen-containing gas, a hydrogen-containing gas, and a nitrogen-containing gas.

5. The method of any one of claims 1 to 4, wherein the protective film contains at least one of silicon, carbon and metal.

6. The method of any one of claims 1 to 4, wherein in (c1) above, no plasma is generated and the first processing gas described above is used.

7. The method of any one of claims 1 to 4, wherein plasma generated by the first processing gas is used in (c1) above.

8. The method of any one of claims 1 to 4, wherein the substrate is heated in at least one of (c1) and (c2) above.

9. The method of any one of claims 1 to 4, wherein the precursor comprises a precursor containing a metal.

10. The method of claim 9, wherein the aforementioned metal-containing precursor comprises a metal complex.

11. The method of claim 10, wherein the metal complex is a complex having at least one monodentate ligand selected from the group consisting of alkyl, hydride, carbonyl, halide, alkoxide, alkylamide and silylamide, or at least one chelate selected from the group consisting of β-diketone, amidoate, acetamidine, β-diketone imine, diaminoalkoxide and metallocene.

12. The method of claim 9, wherein the metal contained in the aforementioned metal-containing precursor is selected from at least one of the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

13. The method of any one of claims 1 to 4, wherein the precursor includes a precursor that does not contain metal.

14. The method of claim 13, wherein the metal-free precursor is selected from at least one β-diketone from the group consisting of acac (acetyl acetone), hfac (hexafluoroacetyl acetone), tfac (trifluoroacetyl acetone) and tmhd (2,2,6,6-tetramethyl-3,5-heptadecyl).

15. The method of any one of claims 1 to 4, wherein the metal-containing film comprises at least one metal selected from the group consisting of Al, Hf, Zr, Fe, Ni, Co, Mn, Mg, Rh, Ru, Cr, Si, Ti, Ga, In, Zn, Pb, Ge, Ta, Cu, W, Mo, Pt, Cd and Sn.

16. The method of claim 15, wherein the metal-containing film is an oxide or nitride of the metal.

17. The method of any one of claims 1 to 4, wherein the fluorine-containing gas comprises at least one selected from the group consisting of hydrogen fluoride gas, fluorocarbon gas, nitrogen-containing gas and sulfur-containing gas.

18. A substrate processing method, comprising: Step (a) involves providing a substrate having an etch target film and a mask disposed on the etch target film. Step (b) involves forming a metal-containing protective film on the aforementioned mask; Step (c) involves removing a portion of the metal-containing protective film after step (b); and Step (d) involves etching the etchable film after step (c); Step (b) includes: Step (b1) involves forming a precursor layer on the side of the aforementioned mask using a first precursor containing metal; and Step (b2) involves modifying the precursor layer into the metal-containing protective film using a modifying gas containing an oxidizing gas or a reducing gas; Step (c) includes: Step (c1) involves forming a second metal-containing substance from the first metal-containing substance contained in the aforementioned metal-containing protective film using at least one first processing gas comprising a halogen-containing gas and an oxygen-containing gas; and step (c2) involves removing the second metal-containing substance using a second processing gas comprising a second precursor; and in step (b) above, the thickness of the protective film formed on the side surface of the aforementioned shield decreases from the upper surface of the aforementioned shield toward the metal-containing protective film.

19. The method of claim 18, wherein the first precursor comprises at least one metal selected from the group consisting of Ti, Ta, Ru, Al, Hf and Sn.

20. The method of claim 18 or 19, wherein the halogen-containing gas comprises at least one selected from the group consisting of fluorine, chlorine and bromine.

21. The method of any one of claims 18 or 19, wherein the second precursor comprises: a metal or a complex of the metal selected from the group consisting of Sn, Ge, Al, B, Ga, In, Zn, Ni, Pb, Si, Hf, Zr and Ti.

22. The method of any one of claims 18 or 19, wherein the etched object film comprises a silicon film.

23. A substrate processing apparatus comprising: a chamber; a substrate support for supporting a substrate within the chamber, the substrate having a metal-containing film and a shield disposed on the metal-containing film; a gas supply unit configured to supply a first processing gas containing hydrogen fluoride gas, a second processing gas containing a precursor, a third processing gas, and a fourth processing gas for forming a protective film to the chamber; and a control unit; wherein the control unit is configured to control the gas supply unit to form the protective film on the shield using the fourth processing gas, and the thickness of the protective film formed on the side surface of the shield decreases from the upper surface of the shield toward the metal-containing film; wherein the control unit is configured to control the gas supply unit to form a second metal-containing substance from a first metal-containing substance contained in the metal-containing film using the first processing gas after the protective film is formed. The control unit is configured to control the gas supply unit to remove the second metal-containing substance after the second metal-containing substance is formed using the second processing gas; the control unit is configured to control the gas supply unit to remove fluorine from the surface of the protective film using the third processing gas after the second metal-containing substance is removed.

Images